1
|
Maciunas LJ, Rotsides P, D'Lauro EJ, Brady S, Beld J, Loll PJ. The VanS sensor histidine kinase from type-B VRE recognizes vancomycin directly. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.07.09.548278. [PMID: 37503228 PMCID: PMC10369886 DOI: 10.1101/2023.07.09.548278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
V ancomycin- r esistant e nterococci (VRE) are among the most common causes of nosocomial infections and have been prioritized as targets for new therapeutic development. Many genetically distinct types of VRE have been identified; however, they all share a common suite of resistance genes that function together to confer resistance to vancomycin. Expression of the resistance phenotype is controlled by the VanRS two-component system. This system senses the presence of the antibiotic, and responds by initiating transcription of resistance genes. VanS is a transmembrane sensor histidine kinase, and plays a fundamental role in antibiotic resistance by detecting vancomycin or its effects; it then transduces this signal to the VanR transcription factor, thereby alerting the organism to the presence of the antibiotic. Despite the critical role played by VanS, fundamental questions remain about its function, and in particular about how it senses vancomycin. Here, we focus on a purified VanRS system from one of the most clinically prevalent forms of VRE, type B. We show that in a native-like membrane environment, the autokinase activity of type-B VanS is strongly stimulated by vancomycin. We additionally demonstrate that this effect is mediated by a direct physical interaction between the antibiotic and the type-B VanS protein, and localize the interacting region to the protein's periplasmic domain. This represents the first time that a direct sensing mechanism has been confirmed for any VanS protein. Significance Statement When v ancomycin- r esistant e nterococci (VRE) sense the presence of vancomycin, they remodel their cell walls to block antibiotic binding. This resistance phenotype is controlled by the VanS protein, a histidine kinase that senses the antibiotic or its effects and signals for transcription of resistance genes. However, the mechanism by which VanS detects the antibiotic has remained unclear, with no consensus emerging as to whether the protein interacts directly with vancomycin, or instead detects some downstream consequence of vancomycin's action. Here, we show that for one of the most clinically relevant types of VRE, type B, VanS is activated by direct binding of the antibiotic. Such mechanistic insights will likely prove useful in circumventing vancomycin resistance.
Collapse
|
2
|
Wang L, Fan R, Li Z, Wang L, Bai X, Bu T, Dong Y, Xu Y, Quan C. Insights into the structure and function of the histidine kinase ComP from Bacillus amyloliquefaciens based on molecular modeling. Biosci Rep 2022; 42:BSR20220352. [PMID: 36052710 PMCID: PMC9620489 DOI: 10.1042/bsr20220352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 08/01/2022] [Accepted: 09/01/2022] [Indexed: 11/21/2022] Open
Abstract
The ComPA two-component signal transduction system (TCS) is essential in Bacillus spp. However, the molecular mechanism of the histidine kinase ComP remains unclear. Here, we predicted the structure of ComP from Bacillus amyloliquefaciens Q-426 (BaComP) using an artificial intelligence approach, analyzed the structural characteristics based on the molecular docking results and compared homologous proteins, and then investigated the biochemical properties of BaComP. We obtained a truncated ComPS protein with high purity and correct folding in solution based on the predicted structures. The expression and purification of BaComP proteins suggested that the subdomains in the cytoplasmic region influenced the expression and stability of the recombinant proteins. ComPS is a bifunctional enzyme that exhibits the activity of both histidine kinase and phosphotransferase. We found that His571 played an obligatory role in the autophosphorylation of BaComP based on the analysis of the structures and mutagenesis studies. The molecular docking results suggested that the HATPase_c domain contained an ATP-binding pocket, and the ATP molecule was coordinated by eight conserved residues from the N, G1, and G2 boxes. Our study provides novel insight into the histidine kinase BaComP and its homologous proteins.
Collapse
Affiliation(s)
- Lulu Wang
- School of Life Science and Biotechnology, Dalian University of Technology, No. 2 Linggong Road, Dalian 116024, Liaoning, China
- Key Laboratory of Biotechnology and Bioresources Utilization of Ministry of Education, College of Life Science, Dalian Minzu University, China
| | - Ruochen Fan
- School of Life Science and Biotechnology, Dalian University of Technology, No. 2 Linggong Road, Dalian 116024, Liaoning, China
- Key Laboratory of Biotechnology and Bioresources Utilization of Ministry of Education, College of Life Science, Dalian Minzu University, China
| | - Zhuting Li
- Key Laboratory of Biotechnology and Bioresources Utilization of Ministry of Education, College of Life Science, Dalian Minzu University, China
- Department of Bioengineering, College of Life Science, Dalian Minzu University, Dalian 116600, Liaoning, China
| | - Lina Wang
- Institute of Cancer Stem Cell, Dalian Medical University, 9 Western Lvshun Road, Dalian 116044, Liaoning, China
| | - Xue Bai
- Key Laboratory of Biotechnology and Bioresources Utilization of Ministry of Education, College of Life Science, Dalian Minzu University, China
- Department of Bioengineering, College of Life Science, Dalian Minzu University, Dalian 116600, Liaoning, China
| | - Tingting Bu
- Key Laboratory of Biotechnology and Bioresources Utilization of Ministry of Education, College of Life Science, Dalian Minzu University, China
- Department of Bioengineering, College of Life Science, Dalian Minzu University, Dalian 116600, Liaoning, China
| | - Yuesheng Dong
- School of Life Science and Biotechnology, Dalian University of Technology, No. 2 Linggong Road, Dalian 116024, Liaoning, China
| | - Yongbin Xu
- Key Laboratory of Biotechnology and Bioresources Utilization of Ministry of Education, College of Life Science, Dalian Minzu University, China
- Department of Bioengineering, College of Life Science, Dalian Minzu University, Dalian 116600, Liaoning, China
| | - Chunshan Quan
- Key Laboratory of Biotechnology and Bioresources Utilization of Ministry of Education, College of Life Science, Dalian Minzu University, China
- Department of Bioengineering, College of Life Science, Dalian Minzu University, Dalian 116600, Liaoning, China
| |
Collapse
|
3
|
Kong L, Su M, Sang J, Huang S, Wang M, Cai Y, Xie M, Wu J, Wang S, Foster SJ, Zhang J, Han A. The W-Acidic Motif of Histidine Kinase WalK Is Required for Signaling and Transcriptional Regulation in Streptococcus mutans. Front Microbiol 2022; 13:820089. [PMID: 35558126 PMCID: PMC9087282 DOI: 10.3389/fmicb.2022.820089] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 02/14/2022] [Indexed: 02/05/2023] Open
Abstract
In Streptococcus mutans, we find that the histidine kinase WalK possesses the longest C-terminal tail (CTT) among all 14 TCSs, and this tail plays a key role in the interaction of WalK with its response regulator WalR. We demonstrate that the intrinsically disordered CTT is characterized by a conserved tryptophan residue surrounded by acidic amino acids. Mutation in the tryptophan not only disrupts the stable interaction, but also impairs the efficient phosphotransferase and phosphatase activities of WalRK. In addition, the tryptophan is important for WalK to compete with DNA containing a WalR binding motif for the WalR interaction. We further show that the tryptophan is important for in vivo transcriptional regulation and bacterial biofilm formation by S. mutans. Moreover, Staphylococcus aureus WalK also has a characteristic CTT, albeit relatively shorter, with a conserved W-acidic motif, that is required for the WalRK interaction in vitro. Together, these data reveal that the W-acidic motif of WalK is indispensable for its interaction with WalR, thereby playing a key role in the WalRK-dependent signal transduction, transcriptional regulation and biofilm formation.
Collapse
Affiliation(s)
- Lingyuan Kong
- State Key Laboratory for Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, China
| | - Mingyang Su
- State Key Laboratory for Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, China
| | - Jiayan Sang
- State Key Laboratory for Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, China
| | - Shanshan Huang
- Department of Clinical Laboratory, The First Affiliated Hospital of Xiamen University, Xiamen, China
| | - Min Wang
- State Key Laboratory for Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, China
| | - Yongfei Cai
- State Key Laboratory for Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, China
| | - Mingquan Xie
- State Key Laboratory for Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, China
| | - Jun Wu
- State Key Laboratory for Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, China
| | - Shida Wang
- State Key Laboratory for Oral Diseases and National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Simon J Foster
- Department of Molecular Biology and Biotechnology, The Florey Institute, The University of Sheffield, Sheffield, United Kingdom
| | - Jiaqin Zhang
- Department of Clinical Laboratory, The First Affiliated Hospital of Xiamen University, Xiamen, China
| | - Aidong Han
- State Key Laboratory for Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, China
| |
Collapse
|
4
|
Recent advances in the Phos-tag technique focused on the analysis of phosphoproteins in a bacterial two-component system. J Proteomics 2022; 252:104429. [PMID: 34813946 DOI: 10.1016/j.jprot.2021.104429] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 11/06/2021] [Accepted: 11/15/2021] [Indexed: 11/21/2022]
Abstract
In a bacterial two-component system (TCS), signals are generally conveyed by means of a His-Asp phosphorelay. Each system consists of a histidine kinase (HK) and its cognate response regulator (RR). The His- and Asp-bound phosphate groups are extremely unstable under acidic conditions easily to be hydrolyzed within a few hours. Because of the labile nature of phosphorylated His and Asp residues, few approaches are available that permit a quantitative analysis of their phosphorylation states in the TCS. Here, we describe that Phos-tag technique is suitable for the quantitative analysis of His- and Asp-phosphorylated proteins. The dynamics of the His-Asp phosphorelay of recombinant TCS derived from Escherichia coli, was examined by Phos-tag SDS-PAGE or Phos-tag fluorescent dye gel staining. The technique permitted not only the quantitative monitoring of the autophosphorylation reactions of HK and RR in the presence of ATP or acetyl phosphate, respectively, but also that of the phosphotransfer reaction from HK to RR in the presence of ATP. Furthermore, we demonstrate profiling of waldiomycin, an HK inhibitor, by using the Phos-tag fluorescent dye gel staining. Consequently, Phos-tag technique provides a simple and convenient approach for screening of HK inhibitors that have potential as new antimicrobial agents. SIGNIFICANCE: Bacterial cells have unique phosphotransfer signaling mechanisms known as two-component systems (TCSs) that permit the organism to sense and respond to various environmental conditions. Each system consists of a histidine kinase (HK) and a response regulator (RR). A typical HK contains an invariant His residue that is autophosphorylated in an ATP-dependent manner. A typical RR has a conserved Asp residue that can acquire a phosphoryl group from its cognate HK. In general, TCS has this type of a His-Asp phosphorelay scheme. Because TCS is also involved in the virulence of pathogens, it is potential targets for novel antibiotics and antivirulence agents. It is, thus, very important to determine HK activity in the bacterial TCS. We believe that our Phos-tag technique provides a simple and convenient approach for drug discovery targeting the bacterial TCS.
Collapse
|
5
|
The many ways that nature has exploited the unusual structural and chemical properties of phosphohistidine for use in proteins. Biochem J 2021; 478:3575-3596. [PMID: 34624072 DOI: 10.1042/bcj20210533] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 09/15/2021] [Accepted: 09/22/2021] [Indexed: 01/12/2023]
Abstract
Histidine phosphorylation is an important and ubiquitous post-translational modification. Histidine undergoes phosphorylation on either of the nitrogens in its imidazole side chain, giving rise to 1- and 3- phosphohistidine (pHis) isomers, each having a phosphoramidate linkage that is labile at high temperatures and low pH, in contrast with stable phosphomonoester protein modifications. While all organisms routinely use pHis as an enzyme intermediate, prokaryotes, lower eukaryotes and plants also use it for signal transduction. However, research to uncover additional roles for pHis in higher eukaryotes is still at a nascent stage. Since the discovery of pHis in 1962, progress in this field has been relatively slow, in part due to a lack of the tools and techniques necessary to study this labile modification. However, in the past ten years the development of phosphoproteomic techniques to detect phosphohistidine (pHis), and methods to synthesize stable pHis analogues, which enabled the development of anti-phosphohistidine (pHis) antibodies, have accelerated our understanding. Recent studies that employed anti-pHis antibodies and other advanced techniques have contributed to a rapid expansion in our knowledge of histidine phosphorylation. In this review, we examine the varied roles of pHis-containing proteins from a chemical and structural perspective, and present an overview of recent developments in pHis proteomics and antibody development.
Collapse
|
6
|
Espinasse A, Lembke HK, Cao AA, Carlson EE. Modified nucleoside triphosphates in bacterial research for in vitro and live-cell applications. RSC Chem Biol 2020; 1:333-351. [PMID: 33928252 PMCID: PMC8081287 DOI: 10.1039/d0cb00078g] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 08/21/2020] [Indexed: 12/12/2022] Open
Abstract
Modified nucleoside triphosphates (NTPs) are invaluable tools to probe bacterial enzymatic mechanisms, develop novel genetic material, and engineer drugs and proteins with new functionalities. Although the impact of nucleobase alterations has predominantly been studied due to their importance for protein recognition, sugar and phosphate modifications have also been investigated. However, NTPs are cell impermeable due to their negatively charged phosphate tail, a major hurdle to achieving live bacterial studies. Herein, we review the recent advances made to investigate and evolve bacteria and their processes with the use of modified NTPs by exploring alterations in one of the three moieties: the nucleobase, the sugar and the phosphate tail. We also present the innovative methods that have been devised to internalize NTPs into bacteria for in vivo applications.
Collapse
Affiliation(s)
- Adeline Espinasse
- Department of Chemistry, University of Minnesota207 Pleasant Street SEMinneapolisMinnesota 55455USA
| | - Hannah K. Lembke
- Department of Chemistry, University of Minnesota207 Pleasant Street SEMinneapolisMinnesota 55455USA
| | - Angela A. Cao
- Department of Chemistry, University of Minnesota207 Pleasant Street SEMinneapolisMinnesota 55455USA
| | - Erin E. Carlson
- Department of Chemistry, University of Minnesota207 Pleasant Street SEMinneapolisMinnesota 55455USA
- Department of Medicinal Chemistry, University of Minnesota208 Harvard Street SEMinneapolisMinnesota 55454USA
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota321 Church St SEMinneapolisMinnesota 55454USA
| |
Collapse
|
7
|
Xie M, Wu M, Han A. Structural insights into the signal transduction mechanism of the K +-sensing two-component system KdpDE. Sci Signal 2020; 13:13/643/eaaz2970. [PMID: 32753477 DOI: 10.1126/scisignal.aaz2970] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Two-component systems (TCSs), which consist of a histidine kinase (HK) sensor and a response regulator (RR), are important for bacteria to quickly sense and respond to various environmental signals. HKs and RRs typically function as a cognate pair, interacting only with one another to transduce signaling. Precise signal transduction in a TCS depends on the specific interactions between the receiver domain (RD) of the RR and the dimerization and histidine phosphorylation domain (DHp) of the HK. Here, we determined the complex structure of KdpDE, a TCS consisting of the HK KdpD and the RR KdpE, which is responsible for K+ homeostasis. Both the RD and the DNA binding domain (DBD) of KdpE interacted with KdpD. Although the RD of KdpE and the DHp of KdpD contributed to binding specificity, the DBD mediated a distinct interaction with the catalytic ATP-binding (CA) domain of KdpD that was indispensable for KdpDE-mediated signal transduction. Moreover, the DBD-CA interface largely overlapped with that of the DBD-DNA complex, leading to competition between KdpD and its target promoter in a KdpE phosphorylation-dependent manner. In addition, the extended C-terminal tail of the CA domain was critical for stabilizing the interaction with KdpDE and for signal transduction. Together, these data provide a molecular basis for specific KdpD and KdpE interactions that play key roles in efficient signal transduction and transcriptional regulation by this TCS.
Collapse
Affiliation(s)
- Mingquan Xie
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen 361102, China
| | - Mengyuan Wu
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen 361102, China
| | - Aidong Han
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen 361102, China.
| |
Collapse
|
8
|
Espinasse A, Wen X, Goodpaster JD, Carlson EE. Mechanistic Studies of Bioorthogonal ATP Analogues for Assessment of Histidine Kinase Autophosphorylation. ACS Chem Biol 2020; 15:1252-1260. [PMID: 32043868 DOI: 10.1021/acschembio.9b01024] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Phosphorylation is an essential protein modification and is most commonly associated with hydroxyl-containing amino acids via an adenosine triphosphate (ATP) substrate. The last decades have brought greater appreciation to the roles that phosphorylation of myriad amino acids plays in biological signaling, metabolism, and gene transcription. Histidine phosphorylation occurs in both eukaryotes and prokaryotes but has been shown to dominate signaling networks in the latter due to its role in microbial two-component systems. Methods to investigate histidine phosphorylation have lagged behind those to study serine, threonine, and tyrosine modifications due to its inherent instability and the historical view that this protein modification was rare. An important strategy to overcome the reactivity of phosphohistidine is the development of substrate-based probes with altered chemical properties that improve modification longevity but that do not suffer from poor recognition or transfer by the protein. Here, we present combined experimental and computational studies to better understand the molecular requirements for efficient histidine phosphorylation by comparison of the native kinase substrate, ATP, and alkylated ATP derivatives. While recognition of the substrates by the histidine kinases is an important parameter for the formation of phosphohistidine derivatives, reaction sterics also affect the outcome. In addition, we found that stability of the resulting phosphohistidine moieties correlates with the stability of their hydrolysis products, specifically with their free energy in solution. Interestingly, alkylation dramatically affects the stability of the phosphohistidine derivatives at very acidic pH values. These results provide critical mechanistic insights into histidine phosphorylation and will facilitate the design of future probes to study enzymatic histidine phosphorylation.
Collapse
Affiliation(s)
- Adeline Espinasse
- Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
| | - Xuelan Wen
- Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
| | - Jason D. Goodpaster
- Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
| | - Erin E. Carlson
- Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
- Department of Medicinal Chemistry, University of Minnesota, 208 Harvard Street SE, Minneapolis, Minnesota 55454, United States
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, 321 Church Street SE, Minneapolis, Minnesota 55454, United States
| |
Collapse
|
9
|
Upton EC, Maciunas LJ, Loll PJ. Vancomycin does not affect the enzymatic activities of purified VanSA. PLoS One 2019; 14:e0210627. [PMID: 30677074 PMCID: PMC6345502 DOI: 10.1371/journal.pone.0210627] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 12/29/2018] [Indexed: 11/18/2022] Open
Abstract
VanS is a membrane-bound sensor histidine kinase responsible for sensing vancomycin and activating transcription of vancomycin-resistance genes. In the presence of vancomycin, VanS phosphorylates the transcription factor VanR, converting it to its transcriptionally active form. In the absence of vancomycin, VanS dephosphorylates VanR, thereby maintaining it in a transcriptionally inactive state. To date, the mechanistic details of how vancomycin modulates VanS activity have remained elusive. We have therefore studied these details in an in vitro system, using the full-length VanS and VanR proteins responsible for type-A vancomycin resistance in enterococci. Both detergent- and amphipol-solubilized VanSA display all the enzymatic activities expected for a sensor histidine kinase, with amphipol reconstitution providing a marked boost in overall activity relative to detergent solubilization. A putative constitutively activated VanSA mutant (T168K) was constructed and purified, and was found to exhibit the expected reduction in phosphatase activity, providing confidence that detergent-solubilized VanSA behaves in a physiologically relevant manner. In both detergent and amphipol solutions, VanSA’s enzymatic activities were found to be insensitive to vancomycin, even at levels many times higher than the antibiotic’s minimum inhibitory concentration. This result argues against direct activation of VanSA via formation of a binary antibiotic-kinase complex, suggesting instead that either additional factors are required to form a functional signaling complex, or that activation does not require direct interaction with the antibiotic.
Collapse
Affiliation(s)
- Elizabeth C. Upton
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Lina J. Maciunas
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Patrick J. Loll
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania, United States of America
- * E-mail:
| |
Collapse
|
10
|
Makwana MV, Muimo R, Jackson RF. Advances in development of new tools for the study of phosphohistidine. J Transl Med 2018; 98:291-303. [PMID: 29200202 DOI: 10.1038/labinvest.2017.126] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Revised: 08/27/2017] [Accepted: 09/03/2017] [Indexed: 01/04/2023] Open
Abstract
Protein phosphorylation is an important post-translational modification that is an integral part of cellular function. The O-phosphorylated amino-acid residues, such as phosphoserine (pSer), phosphothreonine (pThr) and phosphotyrosine (pTyr), have dominated the literature while the acid labile N-linked phosphorylated amino acids, such as phosphohistidine (pHis), have largely been historically overlooked because of the acidic conditions routinely used in amino-acid detection and analysis. This review highlights some misinterpretations that have arisen in the existing literature, pinpoints outstanding questions and potential future directions to clarify the role of pHis in mammalian signalling systems. Particular emphasis is placed on pHis isomerization and the hybrid functionality for both pHis and pTyr of the proposed τ-pHis analogue bearing the triazole residue.
Collapse
Affiliation(s)
- Mehul V Makwana
- Department of Chemistry, University of Sheffield, Sheffield S3 7HF, UK.,Department of Infection, Immunity and Cardiovascular Disease, Medical School, University of Sheffield, Sheffield S10 2RX, UK
| | - Richmond Muimo
- Department of Infection, Immunity and Cardiovascular Disease, Medical School, University of Sheffield, Sheffield S10 2RX, UK
| | | |
Collapse
|
11
|
Wang N, She Z, Ingar Z, Martic S, Kraatz HB. A Bioorganometallic Approach to Study Histidine Kinase Autophosphorylations. Chemistry 2017; 23:3152-3158. [PMID: 28081291 DOI: 10.1002/chem.201605253] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Indexed: 12/12/2022]
Abstract
Auto-phosphorylation of bacterial histidine kinases PhoR, PhoQ, and EnvZ has been investigated using adenosine-5'-[γ-ferrocene] triphosphate (Fc-ATP) as a cosubstrate for the first time. The study has been carried out in solution and on surface. Results from biochemical multiplex assay and surface electrochemical/optical methods are consistent, which successfully demonstrates that Fc-ATP is an efficient cosubstrate for histidine kinase auto-phosphorylations. The study also has discovered that the concentration of Fc-ATP influences the autophosphorylation efficiency. This developed methodology will provide a powerful tool in studying such biological processes towards further understanding of the involved mechanism.
Collapse
Affiliation(s)
- Nan Wang
- Beijing Key Laboratory of Photoelectronic/, Electrophotonic Conversion Materials, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, 100081, P. R. China
| | - Zhe She
- Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario, M5S 3H6, Canada
| | - Zakiyya Ingar
- Department of Physical and Environmental Science, University of Toronto Scarborough, 1265 Military Trail, Toronto, Ontario, M1C 1A4, Canada
| | - Sanela Martic
- Department of Chemistry, Oakland University, 2200 North Squirrel Road, Rochester, Michigan, 48309, USA
| | - Heinz-Bernhard Kraatz
- Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario, M5S 3H6, Canada
| |
Collapse
|
12
|
Drug discovery targeting heme-based sensors and their coupled activities. J Inorg Biochem 2017; 167:12-20. [DOI: 10.1016/j.jinorgbio.2016.11.022] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 11/08/2016] [Accepted: 11/16/2016] [Indexed: 01/10/2023]
|
13
|
An O2-sensing stressosome from a Gram-negative bacterium. Nat Commun 2016; 7:12381. [PMID: 27488264 PMCID: PMC4976288 DOI: 10.1038/ncomms12381] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Accepted: 06/28/2016] [Indexed: 12/16/2022] Open
Abstract
Bacteria have evolved numerous pathways to sense and respond to changing environmental conditions, including, within Gram-positive bacteria, the stressosome complex that regulates transcription of general stress response genes. However, the signalling molecules recognized by Gram-positive stressosomes have yet to be identified, hindering our understanding of the signal transduction mechanism within the complex. Furthermore, an analogous pathway has yet to be described in Gram-negative bacteria. Here we characterize a putative stressosome from the Gram-negative bacterium Vibrio brasiliensis. The sensor protein RsbR binds haem and exhibits ligand-dependent control of the stressosome complex activity. Oxygen binding to the haem decreases activity, while ferrous RsbR results in increased activity, suggesting that the V. brasiliensis stressosome may be activated when the bacterium enters anaerobic growth conditions. The findings provide a model system for investigating ligand-dependent signalling within stressosome complexes, as well as insights into potential pathways controlled by oxygen-dependent signalling within Vibrio species.
Collapse
|
14
|
Ueno TB, Johnson RA, Boon EM. Optimized assay for the quantification of histidine kinase autophosphorylation. Biochem Biophys Res Commun 2015; 465:331-7. [PMID: 26255967 DOI: 10.1016/j.bbrc.2015.07.121] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 07/24/2015] [Indexed: 01/27/2023]
Abstract
Although two-component signaling systems, comprising a sensory histidine kinase and a response regulator, are a primary means by which bacteria detect and respond to environmental stimuli, they are poorly characterized. Here we report optimized conditions for detecting histidine phosphorylation using a facile medium-throughput filter paper-binding assay. Employing this assay we report the kinetic parameters of previously uncharacterized histidine kinases from Vibrio haveyi, Vibrio parahaemolytius, Shewanella oneidensis, and Legionella pneumophila. In characterizing these kinases, we effectively double the number of kinetically characterized histidine kinases that have been reported in the literature.
Collapse
Affiliation(s)
- Takahiro B Ueno
- Department of Chemistry, Stony Brook University, Stony Brook, NY, 11794-3400, USA
| | - Roger A Johnson
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY, 11794-8661, USA
| | - Elizabeth M Boon
- Department of Chemistry, Stony Brook University, Stony Brook, NY, 11794-3400, USA.
| |
Collapse
|
15
|
Nitric Oxide Mediates Biofilm Formation and Symbiosis in Silicibacter sp. Strain TrichCH4B. mBio 2015; 6:e00206-15. [PMID: 25944856 PMCID: PMC4436077 DOI: 10.1128/mbio.00206-15] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
UNLABELLED Nitric oxide (NO) plays an important signaling role in all domains of life. Many bacteria contain a heme-nitric oxide/oxygen binding (H-NOX) protein that selectively binds NO. These H-NOX proteins often act as sensors that regulate histidine kinase (HK) activity, forming part of a bacterial two-component signaling system that also involves one or more response regulators. In several organisms, NO binding to the H-NOX protein governs bacterial biofilm formation; however, the source of NO exposure for these bacteria is unknown. In mammals, NO is generated by the enzyme nitric oxide synthase (NOS) and signals through binding the H-NOX domain of soluble guanylate cyclase. Recently, several bacterial NOS proteins have also been reported, but the corresponding bacteria do not also encode an H-NOX protein. Here, we report the first characterization of a bacterium that encodes both a NOS and H-NOX, thus resembling the mammalian system capable of both synthesizing and sensing NO. We characterized the NO signaling pathway of the marine alphaproteobacterium Silicibacter sp. strain TrichCH4B, determining that the NOS is activated by an algal symbiont, Trichodesmium erythraeum. NO signaling through a histidine kinase-response regulator two-component signaling pathway results in increased concentrations of cyclic diguanosine monophosphate, a key bacterial second messenger molecule that controls cellular adhesion and biofilm formation. Silicibacter sp. TrichCH4B biofilm formation, activated by T. erythraeum, may be an important mechanism for symbiosis between the two organisms, revealing that NO plays a previously unknown key role in bacterial communication and symbiosis. IMPORTANCE Bacterial nitric oxide (NO) signaling via heme-nitric oxide/oxygen binding (H-NOX) proteins regulates biofilm formation, playing an important role in protecting bacteria from oxidative stress and other environmental stresses. Biofilms are also an important part of symbiosis, allowing the organism to remain in a nutrient-rich environment. In this study, we show that in Silicibacter sp. strain TrichCH4B, NO mediates symbiosis with the alga Trichodesmium erythraeum, a major marine diazotroph. In addition, Silicibacter sp. TrichCH4B is the first characterized bacteria to harbor both the NOS and H-NOX proteins, making it uniquely capable of both synthesizing and sensing NO, analogous to mammalian NO signaling. Our study expands current understanding of the role of NO in bacterial signaling, providing a novel role for NO in bacterial communication and symbiosis.
Collapse
|
16
|
Kinoshita E, Kinoshita-Kikuta E, Koike T. The Cutting Edge of Affinity Electrophoresis Technology. Proteomes 2015; 3:42-55. [PMID: 28248262 PMCID: PMC5302491 DOI: 10.3390/proteomes3010042] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Revised: 01/26/2015] [Accepted: 03/11/2015] [Indexed: 11/16/2022] Open
Abstract
Affinity electrophoresis is an important technique that is widely used to separate and analyze biomolecules in the fields of biology and medicine. Both quantitative and qualitative information can be gained through affinity electrophoresis. Affinity electrophoresis can be applied through a variety of strategies, such as mobility shift electrophoresis, charge shift electrophoresis or capillary affinity electrophoresis. These strategies are based on changes in the electrophoretic patterns of biological macromolecules that result from interactions or complex-formation processes that induce changes in the size or total charge of the molecules. Nucleic acid fragments can be characterized through their affinity to other molecules, for example transcriptional factor proteins. Hydrophobic membrane proteins can be identified by means of a shift in the mobility induced by a charged detergent. The various strategies have also been used in the estimation of association/disassociation constants. Some of these strategies have similarities to affinity chromatography, in that they use a probe or ligand immobilized on a supported matrix for electrophoresis. Such methods have recently contributed to profiling of major posttranslational modifications of proteins, such as glycosylation or phosphorylation. Here, we describe advances in analytical techniques involving affinity electrophoresis that have appeared during the last five years.
Collapse
Affiliation(s)
- Eiji Kinoshita
- Department of Functional Molecular Science, Institute of Biomedical and Health Sciences, Hiroshima University, Kasumi 1-2-3, Hiroshima 734-8553, Japan.
| | - Emiko Kinoshita-Kikuta
- Department of Functional Molecular Science, Institute of Biomedical and Health Sciences, Hiroshima University, Kasumi 1-2-3, Hiroshima 734-8553, Japan.
| | - Tohru Koike
- Department of Functional Molecular Science, Institute of Biomedical and Health Sciences, Hiroshima University, Kasumi 1-2-3, Hiroshima 734-8553, Japan.
| |
Collapse
|
17
|
Kinoshita E, Kinoshita-Kikuta E, Shiba A, Edahiro K, Inoue Y, Yamamoto K, Yoshida M, Koike T. Profiling of protein thiophosphorylation by Phos-tag affinity electrophoresis: evaluation of adenosine 5'-O-(3-thiotriphosphate) as a phosphoryl donor in protein kinase reactions. Proteomics 2014; 14:668-79. [PMID: 24453221 DOI: 10.1002/pmic.201300533] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Revised: 12/20/2013] [Accepted: 12/26/2013] [Indexed: 11/08/2022]
Abstract
Adenosine 5'-O-(3-thiotriphosphate) (ATPγS) has been widely used as a phosphoryl donor to trace protein kinase activities. However, the question remains whether particular kinases accept ATPγS as readily as they accept natural ATP. We investigated the characteristics of several kinase reactions in the presence of ATPγS by using Phos-tag affinity electrophoresis. The Phos-tag gel permitted quantitative analysis of thiophosphorylated proteins produced by kinase reactions in vitro and it identified differences in the efficiencies of utilization of ATPγS and ATP in these reactions. Using the method, we evaluated the utility of ATPγS as a phosphoryl donor in studies on bacterial two-component systems. Histidine kinases accepted ATPγS as readily as they accepted ATP in autophosphorylation reactions. However, downstream phosphotransfer reactions with ATPγS were markedly slower than the corresponding reactions with ATP. In an analysis of the sluggish thiophosphate transfer, we found that detergent-denatured thiophosphorylated histidine kinases gradually hydrolyzed at the P-N bond, even at neutral pH, during incubation for 24 h, whereas the native form of the thiophosphorylated enzymes were much more stable. Profiling of protein thiophosphorylation by using Phos-tag affinity electrophoresis might provide new insights into the characteristics of various types of kinase reactions with ATPγS.
Collapse
Affiliation(s)
- Eiji Kinoshita
- Department of Functional Molecular Science, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | | | | | | | | | | | | | | |
Collapse
|
18
|
Abstract
Phosphorylation is a ubiquitous protein post-translational modification, and the importance of phosphorylation of serine, threonine and tyrosine is well established. What is lesser known is that almost all heteroatom-containing amino acids can be phosphorylated and, among these, histidine, aspartate and cysteine have well established roles in bacterial signalling pathways. The first of these, phosphohistidine, is the most unusual in that it is labile under many conditions used to study proteins in vitro and can exist as two different isomers. In the present short review, we highlight the chemical challenges that this modification presents and the manner in which chemical synthesis has been used to identify and mimic the modification in proteins.
Collapse
|
19
|
Small-molecule inhibition of bacterial two-component systems to combat antibiotic resistance and virulence. Future Med Chem 2013; 5:1265-84. [DOI: 10.4155/fmc.13.58] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Infections caused by multidrug-resistant bacteria are a considerable and increasing global problem. The development of new antibiotics is not keeping pace with the rapid evolution of resistance to almost all clinically available drugs, and novel strategies are required to fight bacterial infections. One such strategy is the control of pathogenic behaviors, as opposed to simply killing bacteria. Bacterial two-component system (TCS) signal transduction pathways control many pathogenic bacterial behaviors, such as virulence, biofilm formation and antibiotic resistance and are, therefore, an attractive target for the development of new drugs. This review presents an overview of TCS that are potential targets for such a strategy, describes small-molecules inhibitors of TCS identified to date and discusses assays for the identification of novel inhibitors. The future perspective for the identification and use of inhibitors of TCS to potentially provide new therapeutic options for the treatment of drug-resistant bacterial infections is discussed.
Collapse
|
20
|
A pan-specific antibody for direct detection of protein histidine phosphorylation. Nat Chem Biol 2013; 9:416-21. [PMID: 23708076 PMCID: PMC3686892 DOI: 10.1038/nchembio.1259] [Citation(s) in RCA: 104] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2012] [Accepted: 04/24/2013] [Indexed: 01/08/2023]
Abstract
Despite its importance in central metabolism and bacterial cell signaling, protein histidine phosphorylation has remained elusive with respect to its extent and functional roles in biological systems because of the lack of adequate research tools. We report the development of the first pan-phosphohistidine (pHis) antibody using a stable pHis mimetic as the hapten. This antibody was successfully used in ELISA, western blotting, dot blot assays and immunoprecipitation and in detection and identification of histidine-phosphorylated proteins from native cell lysates when coupled with MS analysis. We also observed that the amount of protein pHis in Escherichia coli lysates depends on carbon source and nitrogen availability in the growth medium. In particular, we found that the amount of pHis on phosphoenolpyruvate synthase (PpsA) is sensitive to nitrogen availability in vivo and that α-ketoglutarate inhibits phosphotransfer from phosphorylated PpsA to pyruvate. We expect this antibody to open opportunities for investigating other pHis proteins and their functions.
Collapse
|
21
|
Arora DP, Boon EM. Unexpected biotinylation using ATP-γ-Biotin-LC-PEO-amine as a kinase substrate. Biochem Biophys Res Commun 2013; 432:287-90. [PMID: 23399564 DOI: 10.1016/j.bbrc.2013.01.115] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Accepted: 01/30/2013] [Indexed: 11/28/2022]
Abstract
Protein phosphorylation is the most widely studied post-translational modification. Reversible protein phosphorylation is implicated in the regulation of a broad range of cellular processes. As such, there is extensive interest in simple and sensitive procedures for the isolation and detection of phosphorylated proteins. Synthetic analogues of ATP, with a biotin linked to the gamma-phosphate of ATP, have been reported to biotinylate kinase substrates in a kinase-catalyzed reaction. This could be an extremely attractive and versatile method for affinity enrichment of phosphorylated proteins. However, as we report here, the commercially available biotin-ATP analogue, ATP-γ-Biotin-LC-PEO-amine, is capable of biotinylating proteins independent of kinase activity. In fact, we demonstrate that this reagent is capable of non-specifically biotinylating any protein. Although the mechanism of biotinylation is not known, this report uncovers a flaw in a commercially available reagent and also highlights the importance of control experiments when developing new biochemical tools to study enzyme activity.
Collapse
Affiliation(s)
- Dhruv P Arora
- Department of Chemistry and the Institute of Chemical Biology and Drug Discovery, Stony Brook University, Stony Brook, NY 11794, USA
| | | |
Collapse
|
22
|
Intramolecular arrangement of sensor and regulator overcomes relaxed specificity in hybrid two-component systems. Proc Natl Acad Sci U S A 2012; 110:E161-9. [PMID: 23256153 DOI: 10.1073/pnas.1212102110] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Cellular processes require specific interactions between cognate protein partners and concomitant discrimination against noncognate partners. Signal transduction by classical two-component regulatory systems typically entails an intermolecular phosphoryl transfer between a sensor kinase (SK) and a cognate response regulator (RR). Interactions between noncognate partners are rare because SK/RR pairs coevolve unique interfaces that dictate phosphotransfer specificity. Here we report that the in vitro phosphotransfer specificity is relaxed in hybrid two-component systems (HTCSs) from the human gut symbiont Bacteroides thetaiotaomicron, which harbor both the SK and RR in a single polypeptide. In contrast, phosphotransfer specificity is retained in classical two-component regulatory systems from this organism. This relaxed specificity enabled us to rewire a HTCS successfully to transduce signals between noncognate SK/RR pairs. Despite the relaxed specificity between SK and RRs, HTCSs remained insulated from cross-talk with noncognate proteins in vivo. Our data suggest that the high local concentration of the SK and RR present in the same polypeptide maintains specificity while relaxing the constraints on coevolving unique contact interfaces.
Collapse
|
23
|
Wilke KE, Francis S, Carlson EE. Activity-based probe for histidine kinase signaling. J Am Chem Soc 2012; 134:9150-3. [PMID: 22606938 DOI: 10.1021/ja3041702] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Bacterial two-component systems (TCSs) are signaling pathways composed of two proteins: a histidine kinase (HK) and a response regulator (RR). Upon stimulation, the HK autophosphorylates at a conserved histidine. The phosphoryl group is subsequently transferred to an aspartate on an RR, eliciting an adaptive response, often up- or downregulation of gene expression. TCS signaling controls many functions in bacteria, including development, virulence, and antibiotic resistance, making the proteins involved in these systems potential therapeutic targets. Efficient methods for the profiling of HKs are currently lacking. For direct readout of HK activity, we sought to design a probe that enables detection of the phosphotransfer event; however, analysis of the phosphohistidine species is made difficult by the instability of the P-N bond. We anticipated that use of a γ-thiophosphorylated ATP analogue, which would yield a thiophosphorylated histidine intermediate, could overcome this challenge. We determined that the fluorophore-conjugated probe, BODIPY-FL-ATPγS, labels active HK proteins and is competitive for the ATP binding site. This activity-based probe provides a new strategy for analysis of TCSs and other HK-mediated processes and will facilitate both functional studies and inhibitor identification.
Collapse
Affiliation(s)
- Kaelyn E Wilke
- Department of Chemistry, Indiana University, Bloomington, 47405, United States
| | | | | |
Collapse
|
24
|
Kee JM, Muir TW. Chasing phosphohistidine, an elusive sibling in the phosphoamino acid family. ACS Chem Biol 2012; 7:44-51. [PMID: 22148577 DOI: 10.1021/cb200445w] [Citation(s) in RCA: 100] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
This year (2012) marks the 50th anniversary of the discovery of protein histidine phosphorylation. Phosphorylation of histidine (pHis) is now widely recognized as being critical to signaling processes in prokaryotes and lower eukaryotes. However, the modification is also becoming more widely reported in mammalian cellular processes and implicated in certain human disease states such as cancer and inflammation. Nonetheless, much remains to be understood about the role and extent of the modification in mammalian cell biology. Studying the functional role of pHis in signaling, either in vitro or in vivo, has proven devilishly hard, largely due to the chemical instability of the modification. As a consequence, we are currently handicapped by a chronic lack of chemical and biochemical tools with which to study histidine phosphorylation. Here, we discuss the challenges associated with studying the chemical biology of pHis and review recent progress that offers some hope that long-awaited biochemical reagents for studying this elusive posttranslational modification (PTM) might soon be available.
Collapse
Affiliation(s)
- Jung-Min Kee
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Tom W. Muir
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| |
Collapse
|
25
|
Perry J, Koteva K, Wright G. Receptor domains of two-component signal transduction systems. MOLECULAR BIOSYSTEMS 2011; 7:1388-98. [PMID: 21347487 DOI: 10.1039/c0mb00329h] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Two-component signal transduction systems are found ubiquitously in prokaryotes, and in archaea, fungi, yeast and some plants, where they regulate physiologic and molecular processes at both transcriptional and post-transcriptional levels. Two-component systems sense changes in environmental conditions when a specific ligand binds to the receptor domain of the histidine kinase sensory component. The structures of many histidine kinase receptors are known, including those which sense extracellular and cytoplasmic signals. In this review, we discuss the basic architecture of two-component signalling circuits, including known system ligands, structure and function of both receptor and signalling domains, the chemistry of phosphotransfer, and cross-talk between different two-component pathways. Given the importance of these systems in regulating cellular responses, many biochemical techniques have been developed for their study and analysis. We therefore also review current methods used to study two-component signalling, including a new affinity-based proteomics approach used to study inducible resistance to the antibiotic vancomycin through the VanSR two-component signal transduction system.
Collapse
Affiliation(s)
- Julie Perry
- MG DeGroote Institute for Infectious Disease Research, Department of Biochemistry and Biomedical Sciences, DeGroote School of Medicine, McMaster University, 1200 Main St W, Hamilton, Ontario, Canada
| | | | | |
Collapse
|